Early wear detection

ABSTRACT

A drill bit with a bit body having a central bore in communication with a plurality of nozzles for directing drilling fluid; a plurality of cutters defining a cutting face of the bit; and a passageway extending from the central bore toward the cutting face, such that excessive wear of the cutting face opens the passageway to allow the drilling fluid to flow therethrough, thereby reducing a surface pressure of the drilling fluid and indicating excessive wear of the bit. The passageway may extend to adjacent, or within one half inch or three inches of, the cutting face, such that excessive wear opens the passageway to the cutting face. In some cases, the passageway may actually extend through the cutting face with a plug inserted into the passageway at the cutting face to prevent the drilling fluid from exiting the passageway absent wear of the bit.

CROSS REFERENCE TO RELATED APPLICATIONS

None.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The inventions disclosed and taught herein relate generally to drill bits for drilling wells, such as oil and gas wells; and more specifically relate to detecting wear of such bits.

2. Description of the Related Art

U.S. Pat. No. 4,785,895 discloses an “earth drilling bit incorporating a tensioned linkage type bit wear indicator. A tensioned linkage extends through the bit between a wear sensor and a device for altering the resistance of the bit to receiving drilling fluid from the drill string. On detecting a predetermined degree of wear, the wear sensor releases the tension in the tensioned linkage. This activates the flow resistance altering device, causing the flow rate and/or pumping pressure of the drilling fluid to change. The tensioned linkage passes through two intersecting passageways in the bit. A guide element is inserted at the intersection of the two intersecting passageways. The guide element routes the tensioned linkage between the two passageways.”

U.S. Pat. No. 4,911,252 discloses a “method and apparatus for detecting excessive displacement of rotating cutter cones on rotary rock bits used in earth boring. The apparatus causes a detectable pressure change in the pressurized drilling fluid system triggered by a pre-determined displacement of a cone from its normal position. This is accomplished by penetration of a sensor by the displaced cone. In the simplest form the penetrated sensor forms an additional exit port for the drilling fluid thereby reducing pressure. In another embodiment the intact sensor maintains a nozzle restricting object in position within the bit body by a hydraulically actuated retainer penetration of the sensor permits loss of the hydraulic fluid and release of the restricting object which then restricts an exit port causing an immediate pressure increase.”

U.S. Pat. No. 6,631,772 discloses a “system and method for detecting the wear of a roller bit bearing between a roller drill bit body and a roller bit rotatably attached to the roller drill bit body. A valve-plug is placed between the roller drill bit body and roller bit such that the valve-plug is removably fitted in a drilling fluid outlet in the roller drill bit body, and the valve-plug extends into a channel in the roller bit whereby uneven rotation or vibration of the roller bit causes the valve-plug to impact the sides of the channel which removes the valve-plug from the drilling fluid outlet to cause drilling fluid to flow through the drilling fluid outlet. The drop in pressure from the drilling fluid flowing through the drilling fluid outlet indicates that the roller bit is worn and may fail.”

U.S. Pat. No. 7,404,457 discloses a “downhole abrading tool has a body with a first end for connection to a drill string, a cutting end, a drilling fluid passageway, and a fusible material disposed within the body. The fusible material is capable of igniting and combusting in response to a selected temperature increase due to excessive wear on the cutting end. Combustion of the fusible material provides an indication to an operator of the downhole abrading tool of the excessive wear on the cutting end of the downhole abrading tool so that the downhole abrading tool can be removed from the well and replaced. The indication to the operator of the downhole abrading tool can be a temperature change or a pressure change in a drilling fluid flowing through the drilling fluid passageway.”

The inventions disclosed and taught herein are directed to an improved system for early detection of wear in drill bits.

BRIEF SUMMARY OF THE INVENTION

A drill bit with a bit body having a central bore in communication with a plurality of nozzles for directing drilling fluid; a plurality of cutters defining a cutting face of the bit; and a passageway extending from the central bore toward the cutting face, such that excessive wear of the cutting face opens the passageway to allow the drilling fluid to flow therethrough, thereby reducing a surface pressure of the drilling fluid and indicating excessive wear of the bit. The drill bit may include one or more roller cones and wherein the passageway may extend into at least one roller cone. In that case, the passageway may extend into the roller cone to a cutter on the roller cone. The drill bit may include one or more fixed blades and the passageway may extend into the blade. The passageway may also extend into the blade to at least one of the cutters. The passageway may extend to adjacent, or within one half inch or three inches of, the cutting face, such that excessive wear opens the passageway to the cutting face. In some cases, the passageway may actually extend through the cutting face with a plug inserted into the passageway at the cutting face to prevent the drilling fluid from exiting the passageway absent wear of the bit. Rather than, or in addition to, individual discrete cutters, some form of a cutting structure, such as diamond impregnated blades, may be used, with the passageway extending into the cutting structure.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a bottom view of one embodiment of hybrid drill bit constructed in accordance with certain aspects of the present invention;

FIG. 2 is a side view of the hybrid drill bit of FIG. 1 constructed in accordance with certain aspects of the present invention;

FIG. 3 is a side view of the hybrid drill bit of FIG. 1 constructed in accordance with certain aspects of the present invention;

FIG. 4 is composite rotational side view of the roller cone inserts and the fixed cutting elements on the hybrid drill bit of FIG. 1 constructed in accordance with certain aspects of the present invention;

FIG. 5 is a simplified sectional view of an embodiment of the hybrid drill bit of FIG. 1 constructed in accordance with certain aspects of the present invention; and

FIG. 5 is another simplified sectional view of an embodiment of the hybrid drill bit of FIG. 1 constructed in accordance with certain aspects of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The Figures described above and the written description of specific structures and functions below are not presented to limit the scope of what Applicants have invented or the scope of the appended claims. Rather, the Figures and written description are provided to teach any person skilled in the art to make and use the inventions for which patent protection is sought. Those skilled in the art will appreciate that not all features of a commercial embodiment of the inventions are described or shown for the sake of clarity and understanding. Persons of skill in this art will also appreciate that the development of an actual commercial embodiment incorporating aspects of the present inventions will require numerous implementation-specific decisions to achieve the developer's ultimate goal for the commercial embodiment. Such implementation-specific decisions may include, and likely are not limited to, compliance with system-related, business-related, government-related and other constraints, which may vary by specific implementation, location and from time to time. While a developer's efforts might be complex and time-consuming in an absolute sense, such efforts would be, nevertheless, a routine undertaking for those of skill in this art having benefit of this disclosure. It must be understood that the inventions disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. Lastly, the use of a singular term, such as, but not limited to, “a,” is not intended as limiting of the number of items. Also, the use of relational terms, such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” and the like are used in the written description for clarity in specific reference to the Figures and are not intended to limit the scope of the invention or the appended claims.

Applicants have created a drill bit with a bit body having a central bore in communication with a plurality of nozzles for directing drilling fluid; a plurality of cutters defining a cutting face of the bit; and a passageway extending from the central bore toward the cutting face, such that excessive wear of the cutting face opens the passageway to allow the drilling fluid to flow therethrough, thereby reducing a surface pressure of the drilling fluid and indicating excessive wear of the bit. The drill bit may include one or more roller cones and the passageway may extend into at least one roller cone. In that case, the passageway may extend into the roller cone to a cutter on the roller cone. The drill bit may include one or more fixed blades and the passageway may extend into the blade. The passageway may also extend into the blade to least one of the cutters. The passageway may extend to adjacent, or within one half inch or three inches of, the cutting face, such that excessive wear opens the passageway to the cutting face. In some cases, the passageway may actually extend through the cutting face with a plug inserted into the passageway at the cutting face to prevent the drilling fluid from exiting the passageway absent wear of the bit. Rather than, or in addition to, individual discrete cutters, some form of a cutting structure, such as diamond impregnated blades, may be used, with the passageway extending into the cutting structure.

Referring to FIGS. 1-3, one embodiment of a system, method, and apparatus for a hybrid drill bit is disclosed. Select components of the drill bit may be similar to that shown in U.S. Patent Application No. 20080264695 and/or U.S. Patent Application No. 20080296068, both of which are incorporated herein by specific reference. The drill bit 11 comprises a bit body 13 having an axis 15 that defines an axial center of the bit body 13. The drill bit 11 may comprise one or more roller cone support arms 17 extending from the bit body 13 in the axial direction. The bit body 13 may also comprise one or more fixed blades 19 that extend in the axial direction. In one embodiment, the centers of the arms 17 and fixed blades 19 are symmetrically spaced apart from each other about the axis 15 in an alternating configuration. In another embodiment, the centers of the arms 17 and fixed blades 19 are asymmetrically spaced apart from each other about the axis 15 in an alternating configuration. For example, the arms 17 may be closer to a respectively leading fixed blade 19, as opposed to the respective following fixed blade 19, with respect to the direction of rotation of the bit 11. Alternatively, the arms 17 may be closer to a respectively following fixed blade 19, as opposed to the respective leading fixed blade 19, with respect to the direction of rotation of the bit 11.

Roller cones 21 are mounted to respective ones of the arms 17. Each of the roller cones 21 may be truncated in length such that the distal ends of the roller cones 21 are radially spaced apart from the axial center 15 (FIG. 1) by a minimal radial distance 23. A plurality of roller cone cutting inserts or elements 25 are mounted to the roller cones 21 and radially spaced apart from the axial center 15 by a minimal radial distance 27. The minimal radial distances 23, 27 may vary according to the application, and may vary from cone to cone, and/or cutting element to cutting element.

In addition, a plurality of fixed cutting elements 31 are mounted to the fixed blades 19. At least one of the fixed cutting elements 31 is located at the axial center 15 of the bit body 13 and adapted to cut a formation at the axial center. Examples of roller cone cutting elements 25 and fixed cutting elements 31 include tungsten carbide inserts, cutters made of super hard material such as polycrystalline diamond, and others known to those skilled in the art.

As shown in FIG. 4, the roller cone cutting elements 25 and the fixed cutting elements 31 combine to define a cutting profile 41 that extends from the axial center 15 to a radially outermost perimeter, or gage section, 43 with respect to the axis. In one embodiment, only the fixed cutting elements 31 form the cutting profile 41 at the axial center 15 and the radially outermost perimeter 43. However, the roller cone cutting elements 25 overlap with the fixed cutting elements 31 on the cutting profile 41 between the axial center 15 and the radially outermost perimeter 43. The roller cone cutting elements 25 are configured to cut at the nose 45 and shoulder 47 of the cutting profile 41, where the nose 45 is the leading part of the profile (i.e., located between the axial center 15 and the shoulder 47) facing the borehole wall and located adjacent the gage 43.

Thus, the roller cone cutting elements 25 and the fixed cutting elements 31 combine to define a common cutting face 51 (FIGS. 2 and 3) in the nose 45 and shoulder 47, which are known to be the weakest parts of a fixed cutter bit profile. Cutting face 51 is located at a distal axial end of the hybrid drill bit 11. At least one of each of the roller cone cutting elements 25 and the fixed cutting elements 31 extend in the axial direction at the cutting face 51 at a substantially equal dimension and, in one embodiment, are radially offset from each other even though they axially align. However, the axial alignment between the distal most elements 25, 31 is not required such that elements 25, 31 may be axially spaced apart by a significant distance when in their distal most position. For example, the bit body has a crotch 53 (FIG. 3) defined at least in part on the axial center between the arms 17 and the fixed blades 19.

In one embodiment, the fixed cutting elements 31 are only required to be axially spaced apart from and distal (e.g., lower than) relative to the crotch 53. In another embodiment, the roller cones 21 and roller cone cutting elements 25 may extend beyond (e.g., by approximately 0.060-inches) the distal most position of the fixed blades 19 and fixed cutting elements 31 to compensate for the difference in wear between those components. As the profile 41 transitions from the shoulder 47 to the perimeter or gage of the hybrid bit 11, the rolling cutter inserts 25 are no longer engaged (see FIG. 4), and multiple rows of vertically-staggered (i.e., axially) fixed cutting elements 31 ream out a smooth borehole wall. Rolling cone cutting elements 25 are much less efficient in reaming and would cause undesirable borehole wall damage.

Referring also to FIGS. 5 and 6, The drill bit 11 also preferably includes an internal central bore 101 in fluid communication with one or more nozzles 103, though one or more paths 105, to direct drilling fluid toward the cutting profile 41 and/or cutting face 51 to clean cuttings and otherwise facilitate drilling. The drilling fluid is typically pumped from the surface and carries cuttings back to the surface, where the drilling fluid is often recycled and pumped back down to the drill bit 11. The nozzles 103 act to restrict the flow of the drilling fluid, thereby creating a certain back pressure at the surface, or surface pressure.

In one preferred embodiment, the bit 11 also includes one or more passageways 107 leading from the central bore toward the cutting profile 41 and/or cutting face 51. The passageway, or passageways, 109 may extend all the way to or adjacent the cutting profile 41 and/or cutting face 51. Alternatively, the passageway 109 may extend to within a predetermined distance, such as between one half inch and three inches of the cutting profile 41 and/or cutting face 51. For example, in one embodiment, the passageway 109 may extend to about one inch of the cutting profile 41 and/or cutting face 51. In another embodiment, the passageway 109 may extend to between one and one half inch and two inches of the cutting profile 41 and/or cutting face 51.

In still other embodiments, the passageways 109 may be through drilled and then capped or plugged with plugs 111. As the bit 11 experiences wear, or is worn, portions of the drill bit 11, such as the bit body 13, arms 17, blades 19, roller cones 21, and/or plugs 111 may wear as well. When the drill bit 11 experiences excessive wear, the passageway 109 may be opened to the cutting profile 41 and/or cutting face 51, thereby creating another flow path for the drilling fluid to escape the bit 11, and reduce the surface pressure of the drilling fluid and indicating excessive wear of the bit 11.

In addition to, instead of, the plug 111, other components of the drill bit 11 may be used to cap the passageways 109, and prevent the drilling fluid from exiting the passageway absent wear of the bit 11. For example, as shown in FIG. 5, the passageways may extend into the blades 19, and be capped by the blade 19 itself, the plug 111, or one of the fixed cutting elements 31. When that portion of the blade 19, the plug 111, or the fixed cutting elements 31 wears, or is torn, away, the passageway 109 connects the central bore 101 with the cutting profile 41 and/or cutting face 51, thereby allowing the drilling fluid to flow therethrough, thereby reducing the surface pressure of the drilling fluid and indicating excessive wear of the bit 11.

Additionally, or alternatively, as shown in FIG. 6, the passageway 109 may extend into the arms 17, a journal 113 upon which the roller cone 21 mounts, and/or even into the roller cone 21 itself. The passageway 109 may be plugged by the arm 17, the journal 113, the roller cone 21, one or more of the roller cone cutting elements 25, or the plug 111. When that portion of the arm 17, the journal 113, the roller cone 21, the roller cone cutting element 25, or the plug 111 wears, or is torn, away, the passageway 109 connects the central bore 101 with the cutting profile 41 and/or cutting face 51, thereby allowing the drilling fluid to flow therethrough, thereby reducing the surface pressure of the drilling fluid and indicating excessive wear of the bit 11.

In some cases, the passageway 109 may connect to one or more passages 115 in the arm 17, blade 19, or roller cone 21 to allow the passageway 109 to be opened with excessive wear in more than one location along the cutting profile 41 and/or cutting face 51. Additionally, or alternatively, one or more passageways 109 may be routed to the nose 43 and/or shoulder 47 sections of the cutting profile 41 and/or cutting face 51, as these sections are typically subject to the most wear.

Other and further embodiments utilizing one or more aspects of the inventions described above can be devised without departing from the spirit of Applicant's invention. For example, the drill bit may be a diamond impregnated bit, and may therefore not have discrete cutters, but may rely on diamond fragments in one or more blades 19. In this case, the passageways 109 may extend into the blades 19, which themselves act as cutters. Additionally, the various methods and embodiments of the present invention can be included in combination with each other to produce variations of the disclosed methods and embodiments. Discussion of singular elements can include plural elements and vice-versa.

The order of steps can occur in a variety of sequences unless otherwise specifically limited. The various steps described herein can be combined with other steps, interlineated with the stated steps, and/or split into multiple steps. Similarly, elements have been described functionally and can be embodied as separate components or can be combined into components having multiple functions.

The inventions have been described in the context of preferred and other embodiments and not every embodiment of the invention has been described. Obvious modifications and alterations to the described embodiments are available to those of ordinary skill in the art. The disclosed and undisclosed embodiments are not intended to limit or restrict the scope or applicability of the invention conceived of by the Applicants, but rather, in conformity with the patent laws, Applicants intend to fully protect all such modifications and improvements that come within the scope or range of equivalent of the following claims. 

1. A drill bit with wear detection feature, the bit comprising: a bit body having a central bore in communication with a plurality of nozzles for directing drilling fluid; a plurality of cutters defining a cutting face of the bit; and a passageway extending from the central bore toward the cutting face, such that excessive wear of the cutting face opens the passageway to allow the drilling fluid to flow therethrough, thereby reducing a surface pressure of the drilling fluid and indicating excessive wear of the bit.
 2. The bit as set forth in claim 1, further including one or more roller cones and wherein the passageway extends into at least one roller cone.
 3. The bit as set forth in claim 2, wherein the passageway extends into the roller cone to a cutter on the roller cone.
 4. The bit as set forth in claim 1, further including one or more fixed blades and wherein the passageway extends into the blade.
 5. The bit as set forth in claim 4, wherein the plurality of cutters are affixed wherein the passageway extends into the blade to at least one of the cutters.
 6. The bit as set forth in claim 1, wherein the passageway extends to within three inch of the cutting face, such that excessive wear opens the passageway to the cutting face.
 7. The bit as set forth in claim 1, wherein the passageway extends to within one inch of the cutting face, such that excessive wear opens the passageway to the cutting face.
 8. The bit as set forth in claim 1, wherein the passageway extends to adjacent the cutting face, such that excessive wear opens the passageway to the cutting face.
 9. The bit as set forth in claim 1, wherein the passageway extends through the cutting face with a plug inserted into the passageway at the cutting face to prevent the drilling fluid from exiting the passageway absent wear of the bit.
 10. A drill bit with wear detection feature, the bit comprising: a bit body having a central bore in communication with a plurality of nozzles for directing drilling fluid; one or more legs extending downwardly from the body; a roller cone rotatably secured to each of the one or more legs; one or more fixed blades extending downwardly from the body; a plurality of cutters rigidly secured to each of the one or more blades, wherein the roller cone and cutters define a cutting face of the bit; and a passageway extending from the central bore toward the cutting face, such that excessive wear of the cutting face opens the passageway to allow the drilling fluid to flow therethrough, thereby reducing a surface pressure of the drilling fluid and indicating excessive wear of the bit.
 11. The bit as set forth in claim 10, wherein the passageway extends into the roller cone.
 12. The bit as set forth in claim 10, wherein the passageway extends into the roller cone to a cutter on the roller cone.
 13. The bit as set forth in claim 10, wherein the passageway extends into the blade.
 14. The bit as set forth in claim 10, wherein the passageway extends into the blade to a cutter.
 15. The bit as set forth in claim 10, wherein the passageway extends to within three inch of the cutting face, such that excessive wear opens the passageway to the cutting face.
 16. The bit as set forth in claim 10, wherein the passageway extends to within one inch of the cutting face, such that excessive wear opens the passageway to the cutting face.
 17. The bit as set forth in claim 1, wherein the passageway extends to adjacent the cutting face, such that excessive wear opens the passageway to the cutting face.
 18. The bit as set forth in claim 1, wherein the passageway extends through the cutting face with a plug inserted into the passageway at the cutting face to prevent the drilling fluid from exiting the passageway absent wear of the bit.
 19. A drill bit with wear detection feature, the bit comprising: a bit body having a central bore in communication with a plurality of nozzles for directing drilling fluid; cutting structure defining a cutting face of the bit; and a passageway extending from the central bore to the cutting face; and a plug in the passageway, at the cutting face, such that excessive wear of the cutting face erodes the plug and opens the passageway to allow the drilling fluid to flow therethrough, thereby reducing a surface pressure of the drilling fluid and indicating excessive wear of the bit. 